The exemplary embodiment relates to the field of digital image processing. It finds particular application in a workflow system for reducing the amount of time spent in performing image enhancement operations to improve a print job's perceptual quality, and will be described with particular reference thereto.
One of the goals of digital color management technology is to preserve the customer's perceptual intent when color documents are rendered on different devices, such as RGB displays and color printers. In some cases, the customer and printer may make coordinated use of the International Color Consortium (ICC) color profiling protocols. However, in many cases, the customer has little knowledge of the capabilities of the printer and submits print job files with the understanding that the files will be manipulated by the print shop. Or, the customer may submit files as being “ready to print,” but which if printed without manipulation, can yield prints with a poor aesthetic quality. As a consequence, the print shop operator often has to reassess the needs and aesthetic choices of the customer and modify the documents accordingly. For example, the print shop operator may modify the document colors of the print job to be more compatible with the color profiles and emulation modes available in the Raster Image Processing (RIP) controller of the printer. Or, the operator may use digital prepress tools, such as image retouching software, to enhance the appearance of the documents, e.g. to improve color balance, dynamic range, and the like.
The lack of specific color management information requires digital press operators to perform an iterative testing and aesthetic enhancement cycle in order to converge toward a set of printing parameters which produces the best perceptual quality. This is often done by testing various parameter configurations to determine which gives the most satisfactory results. These various parameter configurations can be tested by the choice of control parameter settings in the RIP operation. The RIP operation translates document specifications in a page description language (PDL), such as Postscript (PS) or Adobe Portable Document Format (PDF), into a set of color bitmap separations that are images of the document pages. It is an application that runs on a printer's DFE. One of the more commonly used RIP control printing parameters is the choice of printer emulation mode. Other control printing parameters may include rendering intents and GCR (gray component replacement) settings. Or, the adjustments may be made in the digital pre-press.
Unfortunately, there is no simple or intuitive way for the print operator to determine the combination of settings that will produce the most desirable result. Accordingly, print operators will usually make a guess at a combination of RIP settings likely to result in desirable color reproduction. Many combinations of these settings may be tested until satisfactory results are obtained. This process can require a large number of single-print tests and is quite time consuming as each test must be manually set up and initiated on the DFE. This represents a problem for commercial print shops in that it ties up the press in the repeated production of test prints, a process that is costly, time consuming, and an inefficient use of a digital press that is designed not as a proofing machine, but for optimal performance over extended runs. It is also an obstacle to the adoption of automated workflow solutions that depend, in order to produce quality results that meet client expectations, on a level of coordinated color management between the clients of print shops and the print shops that is rarely, if ever, achieved.